Promoting comprehensive green transformation of economic and social development is a key link in achieving high-quality economic development. Green technology innovation is the core content and important guarantee for comprehensive green transformation of economic and social development. This paper constructs a quasi-natural experiment of synergistic empowerment of digital intelligence policies using national big data pilot zone policies and smart city policies. Based on panel data from 265 prefecture-level cities from 2006 to 2021, this study examines the mechanism and heterogeneous effects of digital intelligence policy synergistic empowerment on green technology innovation. The results show that: 1) Digital intelligence policies have a significant synergistic empowerment effect on green technology innovation, and this conclusion remains valid after a series of robustness tests. 2) Under the analytical framework of "technology realization-institutional change-development model," digital intelligence policies can synergistically empower green technology innovation through three dimensions: human capital agglomeration, environmental regulation, and intellectual property protection. 3) For eastern regions, cities with better economic foundations, environmentally protected key cities, non-resource cities, and non-old industrial base cities, the synergistic empowerment effect of digital intelligence policies on green technology innovation is more pronounced. Based on this, we should expand the breadth and depth of digital intelligence policy synergistic pilots, and deeply explore the technology realization mechanism represented by human capital agglomeration, the institutional change mechanism represented by environmental regulation, and the development model represented by intellectual property protection. This paper provides important insights for building green technology innovation mechanisms and accelerating comprehensive green transformation of economic and social development.